Drive range selection assemblies for vehicular transmissions are not per se new. Drive range selection assemblies have historically been employed to effect control of the transmission by the vehicle operator. The shift actuating assembly is generally located on or in close proximity to the transmission, but the manually operated selector assembly, which is controlled by the vehicle operator, may be located in close proximity to or be remote from the shift actuating assembly. In either situation, the composite drive range selection assembly effects the desired operative connection between the vehicle operator and the transmission of the vehicle.
One popular prior art approach is to include a conventional rooster comb in the shift actuating assembly that presents a plurality of alternatingly spaced cam lobes and valleys that are engageable by a spring-loaded detent roller. The detent roller is adapted to be confined in predetermined valleys to actuate a manual selector valve to the degree required to provide the selected drive range.
As a general rule, the cam lobe between the valleys, which delineate the adjacent reverse and the park positions of the shift mechanism, is higher than the other cam lobes, not only to provide a tactile indication sufficient to identify movement therebetween, but also to retain the roller detent in the valley which effects activation of the park lock pawl unless an additional force is applied to the selecting lever. In addition, the lobe between the park and reverse valleys is generally skewed toward the park valley in order not only to enhance movement into the park valley but also to tend to retain the roller detent within the park valley.
Prior arrangements have also tended to locate the park position adjacent the reverse position.